Latent Defect in Construction: Flooding Before Completion Is Not a Construction Defect

Imagine: you have just bought a brand new flat in Mont-de-Marsan. The works were completed a few weeks ago, you signed the completion certificate (the document that formalises the handover of the site). But a week later, during a stormy night, you discover the living room flooded. Water is standing, the parquet flooring is buckling. The builder tells you: 'Sorry, completion has taken place, it's too late.' Is it really over? What does the law say?

This question was recently put to me in my Mont-de-Marsan office by a landowner from the Landes region. The answer lies in an old but still relevant decision of the Court of Cassation of 22 November 1977 (No. 76-11.699). The judges ruled: flooding that occurred before completion of the works does not automatically prove a construction defect. But if the origin of the damage — for example, poorly installed drainage pipes — is discovered later, after completion, then it may be a latent defect (a defect not apparent at the time of delivery, which renders the building unfit for its intended purpose).

In other words, the mere fact that there was flooding before the handover of the keys is not enough to engage the builder's liability. However, if the problem stems from a defect that was not visible at completion, the owner can take action. Let's break down this landmark decision.

The Facts: A Story That Happens Every Day

The case involved a property investment company (SCI) against its builder. The SCI had a building constructed. Before completion — that is, before the client officially accepted the building — flooding occurred in the premises. The water came from the drainage pipes. The builder intervened, repaired, and completion was finally signed. But a few months later, it happened again: another flood, more serious. This time, the origin was clear: the drainage pipes were defective and poorly installed.

The SCI sued the builder for damages, relying on latent defect (a defect not apparent at the time of completion). The builder defended: 'The flood was known before completion! So it's not a latent defect; you accepted the building with full knowledge.' The Court of Appeal ruled in favour of the SCI: it held that the initial flood did not alone prove the existence of a construction defect. The exact origin (defective pipes) was only revealed by subsequent court-ordered expert evidence. It was therefore a latent defect, not covered by completion.

The builder appealed to the Court of Cassation. His argument: a defect is latent only if its very existence was unknown at completion. But here, the flood was known, so the defect was apparent. The Court of Cassation rejected this reasoning. It approved the Court of Appeal: the flood is not in itself a construction defect; it can have various causes (an accidental leak, lack of maintenance, etc.). It is only if the cause is a concealed defect that the defect is latent. In this case, the expert evidence showed that the cause was the defective installation of the pipes, which characterises a latent defect.

The Court's Reasoning — Analysed

The decision rests on a subtle distinction between the damaging event (the flood) and the construction defect (the defective pipes). The builder sought to equate the two: since the flood was apparent before completion, the defect was apparent. But the Court of Cassation reminds us that the defect (the intrinsic fault of the building) is not necessarily revealed by a mere incident. The flood may be due to an external or temporary cause. It is only when the origin is identified as a defect that the defect is constituted.

The legal basis is the former Article 1641 of the Civil Code (now Articles 1641 et seq.) on the warranty against latent defects in sales, but here transposed to the contract for works (construction). The article provides that the seller (or builder) is bound to warrant hidden defects that render the thing unfit for its use. Completion of works normally purges apparent defects — that is, those that the client ought to have noticed at delivery. However, latent defects, not detectable at that time, remain warranted for a period (generally two years, or ten years for damage compromising the building's solidity).

The Court here validates the reasoning of the lower courts: they had discretion to find that the flood before completion did not make the defect apparent, because its cause was not detectable without expert evidence. This is a common-sense solution: a property owner is not a plumbing expert. He may notice a puddle without knowing whether it comes from a faulty seal or a simple overflow. It is only after investigation that the truth emerges.

However, be careful: the decision does not say that any flood before completion is a latent defect. It says that the flood is not, in itself, a defect. The judge must examine the circumstances. If the flood was massive, repeated, and the owner had been informed of its cause before completion, then the defect would be apparent and the warranty excluded.

What This Means for You — Practically

For a landlord owner in Mont-de-Marsan or Capbreton, this decision is a protection. If you take delivery of a new flat, a small leak appears before the signing of the completion certificate, but the builder tells you 'it's nothing, we'll fix it', and six months later the same problem returns with more serious damage, you can rely on a latent defect. The important thing is not to sign the completion certificate with explicit reservations on this point. If you mention the leak in the certificate, the defect becomes apparent and the warranty disappears.

For a purchaser of an old property: the logic is similar. If before the sale, you notice a damp stain, but the seller claims it is just a gutter overflow, and after the purchase you discover that the pipes are cracked, you can take action on the basis of latent defect (within two years of discovery).

For a builder or developer: this case law requires you to be completely transparent. If an incident occurs before completion, do not just patch it up superficially. Have an expert determine the cause and inform the client in writing. Otherwise, you risk being condemned later for latent defect, with damages that can reach several tens of thousands of euros. For example, in Capbreton, a developer had to compensate a co-owner to the tune of €25,000 for leaks not detected before completion, because the expert proved that the waterproofing defect existed from the start.

For a tenant: if you suffer flooding due to a construction defect, your recourse is against the landlord, who can then claim against the builder if the defect is latent. You must report the problem by registered letter as soon as it appears.

Four Tips to Avoid This Type of Dispute

• Have a professional assist you at completion (architect, inspection bureau, or expert). For €500 to €1,000, you will avoid disputes of several thousand euros. In Mont-de-Marsan, several independent experts offer this service.
• Never sign a completion certificate without listing all defects, even minor ones. Use handwritten reservations or a detailed certificate. Even a small damp stain should be noted.
• Keep all evidence: photos of the premises before and after completion, correspondence, expert reports. In case of dispute, these are your best allies.
• If an incident occurs before completion, require a joint expert inspection before signing. Do not rely on the builder's verbal promises. Have the causes recorded by a court-appointed or agreed expert.

Besoin d'un conseil personnalisé ? Contactez Maître Zakine — première consultation 30 min à 45€.

Further Reading: Related Case Law and Developments

This 1977 decision is part of a consistent line of authority. For instance, the Court of Cassation ruled in 2004 (Civ. 3e, 3 March 2004, No. 02-17.849) that leaks appearing before completion but whose origin is only discovered afterwards constitute a latent defect. Conversely, if the defect is apparent and has been the subject of reservations, the decennial liability (10 years for serious damage) may apply, but not the latent defect warranty. The trend is therefore protective of the client: the courts consider that only an expert can determine the cause of an incident, and that the mere observation of a flood is not enough to make the defect apparent.

What few people know is that this case law also applies to sales of old buildings. A seller cannot hide a defect hoping that the buyer saw it before the sale. If the defect was not detectable by a layperson, it remains latent. That is why I always recommend hiring an expert before buying a property.

Checklist Before Taking Action

FAQ – Frequently Asked Questions

1. Can I still take action if I signed the completion certificate without reservation? Yes, if the defect was latent. You have two years from the discovery of the defect to act. Note: completion purges apparent defects, but not latent ones.

2. What should I do if the builder refuses to acknowledge the defect? Apply to the judicial court in summary proceedings for a court-ordered expert inspection. It is quick (a few months) and the judge appoints an impartial expert.

3. What are the time limits? For a latent defect, proceedings must be brought within two years of discovery of the defect. For decennial liability (serious damage), it is 10 years from completion.

4. Can I obtain damages for loss of enjoyment? Yes, if the defect made the home uninhabitable. For example, flooding requiring rehousing may give rise to compensation of €50 to €100 per day.

5. Does home insurance cover these incidents? Yes, for water damage, but the insurer will then claim against the builder if the defect is established. Always report the incident promptly.

Are you in a similar situation? A 30-minute initial consultation with Maître Zakine (€45) may save you months of proceedings — and often much more. Book an appointment →